[Letux-kernel] sgx on pyra with newer kernels

[aTc]

Just saw it appear in the changes list, and gave it a quick try with 
letux-5.10.55. (with DDK 1.14.3699939 (TI) and pyra userspace)

Everything loads fine now, unfortunately performance is really poor.

(about 10 fps max, where before it would easily do 60. glxgears (running 
through gl4es) for example went from 400fps to 9fps. Even mesa manages 
40fps with the window maximized. )

I'll see if I can get a few more people to give it a try, and try to 
figure out where the performance issue comes from.


On 7/31/21 9:10 AM, H. Nikolaus Schaller wrote:
> Hi,
> thanks for finding the "good" and "bad" points, so that I could restrict
> to look in between.
> 
> Finally I could invest some time for this task and was able to exactly imitate your
> bug report (had to install a Stretch image first; Jessie or Bullseye doesn't like my
> DDK 1.14 setup and 1.17 requires libc6 >= 2.29 which is only available in Bullseye
> but also libffi.so.6 which is no longer available on Bullseye - what a pity that we can
> not build our own user-space packages).
> 
> There is already a partial fix in the tree, but with a functional change which
> remained unnoticed.
> 
> The solution is a real hack since the driver wants to do something kernel developers
> have decided that a driver should not (or no longer) do. I have no idea why the sgx
> driver needs it done the way it is done and what it is good for, but simply ignoring
> this difference ends up in the timeout.
> 
> The hack is to expose some lower level kernel API (which is normally hidden) to
> driver modules and provide the old API which has been changed.
> 
> A real solution would be to rewrite bigger portions of the sgx driver to only use
> modern and available API but I have not yet an idea how to do that. Would need
> a lot of more time to find out...
> 
> So let's stick with my hackish solution until we run into problems with it. I can
> now load the firmware without timeout reports on letux-5.10.y or letux-5.14-rc3
>